This invention relates to a torque limiting handle assembly.
A chair control may have a handle which may be rotated by a user to control an adjustment mechanism of the chair. For example, a rotational handle may be employed to control the tension on a spring, which spring resists tilting of the seat or backrest. With any such mechanism there is a risk that the handle may be over-torqued which could damage or jam the mechanism. To avoid this result, it is known to use a two-piece handle assembly connected by a spring loaded ratchet. More specifically, as shown in FIGS. 1 and 2, one piece of the handle assembly acts as the handle 12 and the second piece as a connector 14 connecting to the remainder of the mechanism. The connector 14 has a face gear 16 that meshes with a face gear 18 of the ratchet 20. A spring 22 backstopped by a plate 24 affixed to the connector (by screws 26) urges the ratchet face gear 18 against the connector face gear 16. The handle 12 is keyed to the ratchet 20 so that rotating the handle rotates the ratchet face gear 18. With this arrangement, if the torque on the handle 12 exceeds a threshold (in either rotational direction), the ratchet 20 simply ratchets to allow the handle to turn while the connector 14 remains stationary. Thus, over-torquing of the handle assembly is avoided.
A drawback with such a handle assembly is that it is of relatively complicated construction.
This invention seeks to provide an improved torque limiting handle assembly.